DemocritusContribution to Atomic Theory-
He thought that you would eventually end up with a particle that could not be cut. he thought that in between atoms were empty space, and they are indestructible and will always and forever stay in motion.
Model Name- Democritus Atomic Theory
DaltonContribution to Atomic Theory-
All substances are made of atoms, they cannot be separated, created or destroyed. He thought that all atoms of any given element are identical in mass and properties.he also believed that compounds are formed by combining two or more different atoms, and that a chemical reaction was a rearrangement of atoms.
Model Name-Dalton's Atomic Theory
ThomsonContribution to Atomic Theory-
He discovered that there are tiny particles inside of an atom called electrons. He suggested that the atom was not indivisiable but that it was made up of smaller pieces- protons and electrons
Model Name- Plum Pudding, or Christmas Pudding, or choclate chip cookie.
RutherfoedContribution to Atomic Theory-
Based on an experiment he had performed - with totally unexpected results - he realized that the atom must have almost all of its mass concentrated at its center, in a nucleus, with the main part of the atom consisting of empty space.
Model Name- Planetary Model
BohrContribution to Atomic Theory-
He found that electrons orbit the nucleus without losing energy and they could move only in fixed orbits of specific energies. he discovered that electrons with low energy would orbit closer to the nucleus while electrons with high energy orbit further from the nucleus.
Model Name- Rutherford's Model
ChadwickContribution to Atomic Theory-
He identified the neutron, the particle was proposed as having significant mass and no charge. With the discovery of the neutron three subatomic particles were identified that would help explain observations made at the atomic level. One observation the he made was the existence of radioactive variances of the same element.